Alternative screen section properties should be ignored

When an alternative screen section is created its direct properties are used for building the target screen. Instead the screen section’s instance properties should be used. The alternative should only change what is inside the section, not the attributes of the section in the screen.

If a need to change the section’s attributes arrises, an alternative screen has to be created.

Suggested fix: Make sure that the properties of the section instance are evaluated when working with section alternatives.